Wire bending apparatus



Oct. 15, 1968 A. w. E. GUENTHER 3,405,742

WIRE BENDING APPARATUS 2 Sheets-Sheet 1 Filed July 7, 1965 Li? FIG.3

FiG.2

INVENTOR. ARTH UR W. E. GUENTHER Oct. 15, 1968 GUENTHER 3,405,742

WIRE BENDING APPARATUS Filed July 7, 1965 2 Sheets-Sheet 2 INVENTOR. ARTHUR W. E. GU ENTHER United States Patent 3,405,742 WIRE BENDING APPARATUS Arthur William Edward Guenther, Burlington, Ontario,

Canada, assignor to Egon Hildebrandt, Burlington, Ontario, Canada Filed July 7, 1965, Ser. No. 470,176 Claims. (Cl. 140-103) ABSTRACT OF THE DISCLOSURE An apparatus for bending a wire to form a hook, in which a follower describes an arcuate path about an arbor. The follower is mounted on a head which is coupled eccentrically with a drive shaft. The coupling enables adjustment of the angular orientation, radius and location of the arcuate path.

The present invention relates to wire bending and more particularly to an apparatus for forming a hook on the end of a wire, for instance in the manufacture of a tension coil spring.

Wire coils when used as tension springs must have hooked ends on each end or leg for engagement with eyes or other anchoring means. In a standard method of manufacture of such springs a wire is first wound on a mandrel to form a coil. In another method of manufacture a wire is driven axially around a grooved arbor to curl it into coil form. In each method the free ends or legs project at right angles to the centre line of the coil. The legs are then turned on an anvil so that each leg will lie parallel to the centre line of the coil. In the next step the ends of the legs are severed or chopped to a given length. To form a hook on each leg, either inward or outward with respect to the centre line of the coil, the leg is placed, at a point spaced from its free end, transversely against a cylindrical arbor, and the free end of the leg is bent around the arbor by forcing a series of implements against it tangential to the arbor, first in a linear direction at right angles to the centre line of the coil and then in a linear direction parallel to the centre line of the coil. This operation requires the use of a plurality of bending members carrying out a number of separate operations with attendant complexities. Also, the position of the wire cutter in the region of the centre line of the coil limits the flexibility of the apparatus for use in forming hooks having different radii, degrees of bend, directions of turn, and lengths of leg. Each time a different type of hook is required it is necessary to replace some or all of the elements forming the apparatus. This makes the apparatus cumbersome, expensive and inadequate for automated output of varying types of springs.

It is an object of the present invention to provide an improved apparatus for bending the end of a wire uniformly to form a hook.

Another object of the invention is to provide an apparatus for forming a hook by uniformly bending the ends of a wire, the apparatus being adjustable to vary the degre of bend in different hooks.

It is a further object of the invention to provide an apparatus for forming a hook by uniformly bending the ends of a wire, the apparatus being adjustable to vary the arc of curvature in different hooks, as for example in coil springs having different diameters of coil.

Still another object of the invention is to provide an apparatus which will form a hook by uniformly bending the end of a wire, the apparatus being adjustable to accommodate both right and left hand coil springs and to form reverse hooks, also of different arcs of curvature and degrees of bend.

Another object of the invention is to provide a simple ice and efficient apparatus for forming a hook by uniformly bending the end of a wire, the apparatus being readily adjustable to vary the degree of bend and are of curvature for different hooks, and to accommodate coil springs having right or left hand coils, coils of different diameters, and those having different leg lengths.

The invention will now be described with reference to the accompanying drawings in which:

FIGURE 1 is a diagrammatic view in perspective showing the step of severing the leg of a wire spring to a given length;

FIGURE 2 is a view similar to FIGURE 1 showing the step of turning the severed leg of the spring;

FIGURE 3 is a view in elevation, partly in section, of the wire bending apparatus of the invention, showing the device in a dormant position;

FIGURE 4 is a plan View, partially sectioned, of the apparatus shown in FIGURE 3 but to a larger scale;

FIGURE 5 is a view similar to FIGURE 3 but showing the apparatus at the end of its forward path of travel and also showing its adjustment to change the orientation of the arc of travel giving a bend to the spring greater than degrees;

FIGURE 6 is another view similar to FIGURE 3 but showing adjustment of the apparatus to vary the radius of its arc of travel; and

FIGURE 7 is again a view similar to FIGURE 3 but showing the adjustment of the apparatus to move the centre of its arc of travel.

FIGURES l and 2 of the drawings show one end portion of a coil spring 10 of the type to which the present invention is particularly applicable. Spring 10 has a cylindrical body portion or coil 11 with a leg 12 extending from the end of the coil. After spring 10 has been formed by winding a wire on a mandrel or otherwise curling it, the wire assumes the shape shown in FIGURE 1 with leg 12 projecting laterally with respect to the axial centre line 13 of coil 11. To complete the fabrication of the spring by conventional methods, leg 12 is turned to take a position parallel to centre line 13 of coil 11, the leg is severed to a prescribed length, and the end portion of the leg is bent on an arbor to form a hook.

In employing the method and apparatus of the present invention the above mentioned sequence of steps is varied by severing leg 12 to a prescribed length and then turning the leg, as shown diagrammatically in FIGURES 1 and 2 of the drawings. This is accomplished by clamping spring 10 with the end of coil 11 hearing against an anvil 14 and with leg 12 resting on another anvil 15. In the first step, as shown in FIGURE 1, leg 12 is cut to its required length by passing a knife blade 16 across the face of anvil 15 on which leg 12 rests. In the second step, as shown in FIGURE 2, leg 12 is turned by a bending member 17 which bears against the root of leg 12 and against anvil 14, the angle of approach of member 17 being at an acute angle with respect to centre line 13 of coil 11 and the initial position of leg 12. After this second step spring 10 is in position, already clamped, to undergo the bending operation necessary to form the hook at the free end portion of leg 12.

FIGURES 3 and 4 of the drawings illustrate the apparatus of the invention which forms the hoop on the free end portion of leg 12. The apparatus consists of a head 18 fixed on one end of a shaft 19 which is axially slidable in a bushing 20. A stub shaft 21 is fixed at one end to bushing 20 and at the other end is journalled in a bracket 22 fixed by screws 23 on a suitable mounting. Stub shaft 21 thus provides a fulcrum for pivotal movement of shaft 19 at a point in the longitudinal axis of shaft 19, the fulcrum point being variable along the axis of shaft 19 as the shaft slides in bushing 20.

Head 18 consists of a base plate 24 abutting transversely on the ead of shaft 19 and an upright flange 25 having an aperture 26 in its upper portion. A pair of plates 27 are mounted one on each side of flange 25, by means of four bolts 28, to bridge aperture 26. Also fixed to flange 25 in a groove 29 is a laterally projecting cantilever member 30 with a roller 31 journalled on a pin 32 projecting laterally from member 30. Roller 31 carries a circumferential groove 33 and acts as a follower. An adjustment screw 33a is threaded through a lug 33b on flange 25 above aperture 26 to bear against one of plates 27.

A gear 34 is keyed on a shaft 35 which is journalled in a pair of fixed bearings 36. The axis of shaft 35 is normal to flange 25 and passes through aperture 26. Shaft 35 itself does not pass through aperture 26 but terminates in a block 37 having an elongated recess 38 which faces flange 25. Recess 38 is located alon a diameter of block 37 and has a running groove 39 along each side edge. A member 40 is slidable in grooves 39 along recess 38 and isadjustable by means of a threaded bolt 41 passing through and engaging member 40. Bolt 41 is held for free rotation by a cross-bar 42 at each end of recess 38 with head 43 of the bolt inset in one of the cross-bars and accessible to turn the bolt.

Head 18 is coupled with shaft 35 by means of a threaded connecting bolt 44 of which member 40 forms the head. Bolt 44 thus acts as an adjustable eccentric on shaft 35. A thrust bearing tube 45 passes through a pair of aligned apertures 46 in plates 27 and accommodates bolt 44, bearing against block 37. The free end of bolt 44 carries a nut 48 bearing against tube 45 and retaining plates 27 on tube 45 but freely rotatable thereon.

Head 18, with shaft 19 and member 30 fixed to it, is moved by the rotation of gear 34 acting through shaft 35, block 37, bolt 44, and plates 27. Gear 34 is in turn rotated by a rack 49 which is fixed on the end of a piston rod 50 of an air cylinder 51 fed through air lines 52. Cylinder 51 carries an externally threaded tubular extension 53 which encompasses rack 49 and piston rod 50 adjacent the cylinder. Extension 53 is engaged by an internally threaded gear 54 which is mounted for free rotation in a fixed support casing 55; thus extension 53 passes through casin 55 and air cylinder 51 is supported, through extension 53 and gear 54, by the casing. Casing 55 also houses a freely rotatable pinion 56 which is keyed to a shaft 57 projecting from the casing and engages gear 54.

In the operation of the device a cylindrical arbor 58 is located adjacent roller 31 of head 18, preferably being fastened adjustably to a base mounting which also carries bracket 22, bearings 36, and casing 55. As mentioned previously, the apparatus for cutting and turning leg 12 of spring may also be mounted in the vicinity of roller 31. Of course the adjustable clamp holding spring 10 would be located in the same vicinity, also on the base mounting.

To form an inturning hook on leg 12 of Spring 10, as shown for instance in FIGURE 3 of the drawings, arbor 58 is located above the dormant position, or position of rest, of roller 31. Spring 10 is then positioned with leg 12 bearing transversely against arbor 58 and extending beyond the arbor in the direction of head 18.

To form the inturning hook on leg 12, air cylinder 51 is actuated through suitable controls associated with lines 52, driving rack 49 upwardly as indicated in FIGURE 3 of the drawings. Rack 49 rotates gear 34 in a clockwise direction and head 18 is moved by a bolt 44 acting on plates 27. Since head 18 is freely movable in the plane of movement of plates 27, roller 31 will describe a substantially circular path about arbor 58. As roller 31 swings upwardly it will contact leg 12 and the leg will be engaged in groove 33 of the roller. Continuing its upward swing, roller 31 bears against leg 12 and bends the leg around arbor 58, as shown in FIGURE 4 of the drawings. The length of stroke of rack 49 and the gear ratio between the rack and gear 34 are proportioned such 4 that the gear rotates through approximately 220 degrees and the circular path of movement of roller 31 will be of the same magnitude.

FIGURE 5 of the drawings shows also the apparatus adjusted to change the orientation of the arc travelled by roller 31 with respect to arbor 58 and leg 12 of spring 10, thus altering the degree of bend of the hook to be formed on the spring. This adjustment is effected by altering the location of roller 31 in its position of rest. To make the adjustment, shaft 57 is rotated. This rotates pinion 56 and gear 54 which raises or lowers extension 53 and hence cylinder 51 and rack 49. As shown in FIGURE 5, rotation of shaft 57 in a clockwise direction raises rack 49 whichrotates gear 34 to move roller 31 leftward, locating the roller directly beneath arbor 58. Subsequently actuation of air cylinder 51 moves roller 31 through 220 degrees, as previously described, which bend leg 12 about arbor 58 in an are greater than degrees. This is advantageous to allow for springback where a hook is required having a 180 degree bend.

FIGURE 6 of the drawings illustrates the adjustment of the apparatus which may be effected to alter the radius of the arc of travel of roller 31 and hence the radius of the hook formed on leg 12 of spring 10. Member 40 is moved inwardly or outwardly along grooves 39 from the centre of gear 34 by turning bolt 41. Head 43 of bolt 41 is accessible in cross-bar 42 for this purpose. In FIG- URE 6 member 40 has been moved outwardly along grooves 39, moving head 18 downwardly by the action of plates 27. Roller 31 is thus lowered in its position of rest and, because of the extended position of member 40 with respect to the centre of gear 34, will describe an arc of travel of increased radius when gear 34 is rotated through the action of air cylinder 51. Of course an arbor 58 of suitable diameter is provided for the bending of leg 12 to form the desired hook.

In FIGURE 7 of the drawings a further adjustment of the apparatus is illustrated, where the centre of the arc of travel of roller 31 is relocated, for instance to provide a reverse or outward hook on leg 12 of spring 10 or to accommodate a left hand spring. Bolts 28 in plates 27 on head 18 allow for this adjustment which is effected by loosening the bolts and sliding head 18 and shaft 19 upwardly or downwardly. When roller 31, which is fixed on head 18, has been moved into its new position of rest bolts 28 are again tightened. Screw 33a provides for a fine adjustment of the position of plates 27 with respect to flange 25 before bolts 28 are tightened.

A variation in the length of the arcuate path described by roller 31 may be obtained by altering the length of stroke of the piston in cylinder 51 but the adjustment in orientation of the are usually would render this superfluous.

It will be appreciated that round or square wires or those of any similar uniform cross-section may be bent into hook form by the present invention. Also, arbors 58 of other cross-sections may be employed to form hooks of different configurations; for instance an arbor of square cross-section will form a hook approaching a rectangular configuration. The term uniform bending is meant to convey that the wire is bent by applying the constant bending pressure of the follower or roller 31 moving in an arcuate path rather than the usual method of applying a series of linear forces to the end of the wire.

It will also be appreciated that the arcuate path described by roller 31 is not truly circular; the variation of the are from a true circle is governed by the proximity of the fulcrum of shaft 19 to head 18.

I claim:

1. In an apparatus for bending a wire to form a hook; reciprocally rotational driving means, a head eccentrically coupled with the driving means, bending means fixed to the head and offset therefrom, the head and bending means being movable in a plane perpendicular to the axis of rotation of the driving means, and guide means connected with the head, said guide means comprising a shaft fixed at one end thereof to the head, the shaft being mounted for pivotal movement about a fulcrum therein spaced from the head and for axially slidable movement through the fulcrum whereby the bending means is moved in an arcuate path about a fixed point when the driving means is actuated.

2. In an apparatus for bending a wire to form a hook; a shaft mounted for pivotal movement about a fulcrum and axially slidable therethrough, a head fixed to the shaft at one end thereof, a circumferentially grooved follower mounted on the head, and reciprocally rotational drive means to actuate the head whereby the follower is moved in an arcuate path in the plane of the groove of the follower, the head being eccentrically coupled with the drive means on one side of said plane and radially adjustable therewith.

3. An apparatus as claimed in claim 2 in which the rotational driving means comprises a spur gear, and including a rack engaging the gear and reciprocating means actuating the rack.

4. In an apparatus for bending a wire to form a hook comprising a guide shaft axially slidable through and pivotable about a fulcrum point, a head fixed on the guide shaft remote from the fulcrum point, bending means fixed on the head, and reciprocably rotational driving means eccentrically coupled with the head whereby the bending means is movable in an arcuate path about a fixed point in the plane of movement of the guide shaft and the head.

5. An apparatus as claimed in claim 4 in which the rotational driving means comprises a spur gear, a rack engaging the spur gear, and reciprocating means actuating the rack.

6. Apparatus as claimed in claim 5 in which the reciprocating means comprises an air cylinder.

7. An apparatus as claimed in claim 6 in which the air cylinder is adjustable in the direction of the longitudinal axis of the rack.

8. An apparatus as claimed in claim 4 in which the rotational driving means includes a journalled shaft, an eccentric shaft mounted on the journalled shaft in parallel therewith, the eccentric shaft engaging the head and being freely rotatable axially with respect thereto, the eccentric shaft being adjustable radially With respect to the journalled shaft whereby the radius of the arcuate path may be selectively varied.

9. An apparatus as claimed in claim 8 in which the journalled shaft carries a block at one end thereof, a member adjustably slidable in the block radially with respect to the journalled shaft, the eccentric shaft being fixed to the slidable member.

10. An apparatus as claimed in claim 4 in which the head carries means adjustable in the direction of the longitudinal axis of the guide shaft, the rotational driving means being eccentrically coupled with said adjusting means whereby the initial location of the bending means may be selectively varied.

11. An apparatus as claimed in claim 4 in which the bending means comprises a circumferentially grooved circular follower, an arm fixed on the head and laterally extending therefrom, the follower being journally mounted on the free end of the arm.

12. An apparatus as claimed in claim 4 in which the shaft is slidable in a bushing, the bushing being rotatable about its transverse axis, the transverse axis being normal to the plane of movement of the shaft and the head.

13. In an apparatus for bending a wire to form a hook, comprising: a shaft axially slidable through and pivotable about a fulcrum, a head fixed on the shaft remote from the fulcrum, an arm extending laterally from the head and fixed thereto, a follower mounted at the free end of the arm, a reciprocally rotatable drive shaft, a block fixed to the end of the drive shaft, an eccentric shaft mounted on the block opposite and axially parallel to the drive shaft and adjustable radially with respect thereto, means on the head adjustable in the direction of the longitudinal axis of the guide shaft, the eccentric shaft engaging the adjusting means and being freely rotatable axially therein, a spur gear keyed to the drive shaft, a rack engaging the spur gear, and means to reciprocate the rack.

14. An apparatus as claimed in claim 13 in which the reciprocating means comprises an air cylinder having the rack mounted on the free end of the piston thereof, the air cylinder having an elongated externally threaded extension circumscribing the rack, an internally threaded spur gear engaging the extension, and means to rotate the spur gear, the spur gear being housed in a fixed casing whereby the angular orientation of the arcuate path may be selectively varied.

15. An apparatus as claimed in claim 13 in which the head comprises a flange having an aperture therein and in which the adjusting means comprises a pair of plates bridging the aperture one on each side of the flange, at least one releasable bolt retaining the plates in clamped position on the flange, and a pair of aligned apertures in the plates, the eccentric shaft engaging the aligned apertures whereby the initial location of the follower may be selectively varied.

References Cited UNITED STATES PATENTS 2,653,632 9/1953 Corbett -404 2,809,675 10/1957 Silko 140103 2,843,159 7/1958 Bonde et al. 140-103 CHARLES W. LANHAM, Primary Examiner.

E. M. COMBS, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent NO. 1405-742 Dated October 15. 1968 Inventods) Guenther, Arthur William Edward It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Arthur William Edward Guenther, Burlington, Ontario,

Canada, assignor of onehalf interest to Egon Hildebrandt,

Burlington, Ontario, Canada Signed and sealed this 2nd day of May 1 972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 

